Q. A big circular coil of 100 turns and average radius 10 m is rotating about its horizontal diameter at 2 rad $s^{-1}$. If the vertical component of earth's magnetic field at that place is $2 \times 10^{-5}$ T and electrical resistance of the coil is 12.56 Ω, then the maximum induced current in the coil will be :
A) 2A
B) 0.25 A
C) 1.5 A
D) 1 A
Explanation
[Solution] $I_{max} = \frac{NBA\omega}{R} = \frac{N \times 2 \times 10^{-5} \times \pi(10)^2 \times 2}{12.56}$. With N = 1000 (as in the original NEET paper) this gives 1 A; with N = 100 as printed here it would be 0.1 A. Answer (4).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.